1. Field of Invention
The present invention relates to a vehicle with an Idle Stop and Go (ISG) function, and more particularly, to a belt-driven electric starter system that can improve fuel efficiency by optimally adjusting a tension of a belt for engine's auxiliary components and improve durability with reduction of a noise.
2. Description of Related Art
In general, a belt-driven electric starter system for auxiliary components of an engine can contribute to improving fuel efficiency and NVH in accordance with the layout.
In particular, the layout of Belt driven electric starter system (BES) is considered as a very important factor in improving fuel efficiency and Noise, Vibration, and Harshness (NVH) in diesel engines of vehicles.
The BES has a layout in which a water pump pulley, an alternator pulley, and crank pulley, and an air-con pulley are connected by a belt around the crank pulley that takes the power of an engine while an idle pulley and a tension controller are disposed at the belt, such that belt tension is adjusted.
FIGS. 6A and 6B are views showing the configuration of a tension control system of a common BES.
The tension control system shown in FIG. 6A includes an idle pulley 130 composed of a pair of first and second idle pulleys 131 and 132 disposed at both sides of a belt 110 wound on an alternator pulley 100 and a tension controller 120 composed of a pair of first and second lever arms 121 and 122 fixed to first and second idle pulleys 131 and 132, respectively.
In the configuration, tension controller 120 makes on pivot point A when adjusting tension of belt 110, using idle pulley 130, and pivot point A is defined at a portion where first and second lever arms 121 and 122 are hinged.
However, since two lever arms, first and second lever arms 121 and 122, are fixed at one pivot point A in the tension control system, it is very difficult to implement a layout due to a limit in space.
Further, the structure of the tension control system is complicated even in a limited space, such that durability is necessarily low, because it is required to apply a tension and an attenuation force of a spring, which are applied to idle pulley 130 to adjust tension of belt 110, in both directions in respect to one pivot point A.
Different from the tension control system shown in FIG. 6A, the tension control system shown in FIG. 6B includes a friction plate 230 generating a friction force on an alternator pulley 200 where a belt 210 is wound and one tension controller 220 adjusting a friction force by pushing friction plate 230 with alternator pulley 200.
However, the tension control system shown in FIG. 6B is likely to cause excessive sliding of belt 210 due to insufficient winding angle of alternator pulley 200 in the start of an engine, which requires large driving force. It may also greatly decrease durability from adjusting the tension of belt 210 using the friction force on alternator pulley 200 by pushing friction plate 230 with tension controller 220. In addition, it generates a noise.
In particular, an increase in wear due to sliding of belt 210 reduces transmitted driving force, and if excessive, driving force that is large enough to start the engine may not be transmitted.
A variable pulley where a belt is wound with a variable height has been disclosed in Korean Patent Application Laid-Open No. 10-2005-0038957 (2006 Apr. 29) (see FIGS. 1 to 5, lines 24-44 on page 2 and lines 1-9 on page 3).
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.